From: Zhen Lei <thunder.leizhen@huawei.com>
To: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
John Garry <john.garry@huawei.com>,
Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will.deacon@arm.com>, Joerg Roedel <joro@8bytes.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-doc <linux-doc@vger.kernel.org>,
Sebastian Ott <sebott@linux.ibm.com>,
Gerald Schaefer <gerald.schaefer@de.ibm.com>,
"Martin Schwidefsky" <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
"Michael Ellerman" <mpe@ellerman.id.au>,
Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
David Woodhouse <dwmw2@infradead.org>,
iommu <iommu@lists.linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
x86 <x86@kernel.org>, linux-ia64 <linux-ia64@vger.kernel.org>
Subject: [PATCH v9 1/7] iommu: enhance IOMMU default DMA mode build options
Date: Thu, 13 Jun 2019 16:42:34 +0800 [thread overview]
Message-ID: <20190613084240.16768-2-thunder.leizhen@huawei.com> (raw)
In-Reply-To: <20190613084240.16768-1-thunder.leizhen@huawei.com>
First, add build option IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the
opportunity to set {lazy|strict} mode as default at build time. Then put
the three config options in an choice, make people can only choose one of
the three at a time.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
drivers/iommu/Kconfig | 44 ++++++++++++++++++++++++++++++++++++--------
drivers/iommu/iommu.c | 3 ++-
2 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 83664db5221df02..fe715fb295c6ed2 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -75,16 +75,44 @@ config IOMMU_DEBUGFS
debug/iommu directory, and then populate a subdirectory with
entries as required.
-config IOMMU_DEFAULT_PASSTHROUGH
- bool "IOMMU passthrough by default"
+choice
+ prompt "IOMMU default DMA mode"
depends on IOMMU_API
- help
- Enable passthrough by default, removing the need to pass in
- iommu.passthrough=on or iommu=pt through command line. If this
- is enabled, you can still disable with iommu.passthrough=off
- or iommu=nopt depending on the architecture.
+ default IOMMU_DEFAULT_STRICT
+ help
+ This option allows an IOMMU DMA mode to be chosen at build time, to
+ override the default DMA mode of each ARCH, removing the need to
+ pass in kernel parameters through command line. You can still use
+ ARCH specific boot options to override this option again.
- If unsure, say N here.
+ If unsure, keep the default.
+
+config IOMMU_DEFAULT_PASSTHROUGH
+ bool "passthrough"
+ help
+ In this mode, the DMA access through IOMMU without any addresses
+ translation. That means, the wrong or illegal DMA access can not
+ be caught, no error information will be reported.
+
+config IOMMU_DEFAULT_LAZY
+ bool "lazy"
+ help
+ Support lazy mode, where for every IOMMU DMA unmap operation, the
+ flush operation of IOTLB and the free operation of IOVA are deferred.
+ They are only guaranteed to be done before the related IOVA will be
+ reused.
+
+config IOMMU_DEFAULT_STRICT
+ bool "strict"
+ help
+ For every IOMMU DMA unmap operation, the flush operation of IOTLB and
+ the free operation of IOVA are guaranteed to be done in the unmap
+ function.
+
+ This mode is safer than the two above, but it maybe slower in some
+ high performace scenarios.
+
+endchoice
config OF_IOMMU
def_bool y
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index f9cacce909d3ae9..05171dd0bd03aee 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -31,7 +31,8 @@
#else
static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_DMA;
#endif
-static bool iommu_dma_strict __read_mostly = true;
+static bool iommu_dma_strict __read_mostly =
+ IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT);
struct iommu_group {
struct kobject kobj;
--
1.8.3
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-06-13 8:43 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 8:42 [PATCH v9 0/7] iommu: enhance IOMMU default DMA mode build options Zhen Lei
2019-06-13 8:42 ` Zhen Lei [this message]
2019-06-13 8:42 ` [PATCH v9 2/7] x86/dma: use IS_ENABLED() to simplify the code Zhen Lei
2019-06-13 8:42 ` [PATCH v9 3/7] s390/pci: add support for IOMMU default DMA mode build options Zhen Lei
2019-06-13 8:42 ` [PATCH v9 4/7] powernv/iommu: " Zhen Lei
2019-06-13 8:42 ` [PATCH v9 5/7] iommu/vt-d: " Zhen Lei
2019-06-13 8:42 ` [PATCH v9 6/7] iommu/amd: " Zhen Lei
2019-06-13 8:42 ` [PATCH v9 7/7] ia64: hide build option IOMMU_DEFAULT_PASSTHROUGH Zhen Lei
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